Nowadays, a search key word used to perform a search with a search engine on the internet is transmitted in a television (hereinafter referred to as “TV”) broadcasting image such as a CM (Commercial Message). The search key word is displayed on a TV broadcast receiver as a part of the TV broadcasting image, which prompts a user to search the search key word with the search engine.
However, because the search key word is displayed for a short time in many cases, a user may miss the search key word. When a situation is not the case that the user immediately performs the search on the internet, sometimes the user forgets the displayed search key word before the search.
In order to avoid the problem, it is conceivable that a character string of the search key word is recognized from the TV broadcasting image to extract the search key word.
For example in an internet television device disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2010-039647), the character string is detected from a video picture of TV broadcasting by character recognition, a word is detected from the detected character string, and a key word used to search information on a network is decided from the detected word according to a predetermined condition.
Patent Document 2 (Japanese Unexamined Patent Publication No. 2009-188886) discloses an information processing device that performs the search on the internet using a key word detected from various search guiding screen presented by the TV broadcasting. Specifically, a change amount between a latest input image and a preceding input image within a predetermined time is calculated, and character recognition processing is performed in a region where the change amount is less than or equal to a threshold. The image including the character string is necessary to be continuously displayed for a certain period of time so that the user can recognize the character string. Therefore, extremely small change amount of the character string is considered, so that the character string including the key word can be extracted by the character recognition processing.